In the past, numerous apparatus have been provided for converting the forces of natural wind into useful work. Substantial work in this technology has taken place in the early part of the century, as exemplified by the patents to Holterud U.S. Pat. No. 1,415,645 and Nolan U.S. Pat. No. 1,416,052. Throughout the middle of the century, there was somewhat of a reduction in this technology as fossil fuel became an increasingly significant energy source. Recently, however, renewed interest in energy sources derived from naturally occurring phenomena such as wind, has taken place in view of present and predicted shortages in the supply of fossil fuel. Examples of recent developments in wind powered energy conversion apparatus are Wiggin U.S. Pat. No. 3,212,470, Ri U.S. Pat. No. 3,942,025, Baum, Sr. et al U.S. Pat. No. 4,177,009, Wurtz U.S. Pat. No. 4,186,313, Kephart, Jr. U.S. Pat. No. 4,177,014 and Bolie U.S. Pat. No. 4,204,805.
I have determined that such wind responsive apparatus, although generally usable, typically display various deficiencies. For example, wind responsive apparatus are generally formed with some type of impeller that has a surface which reacts with wind to develop a torque. This torque is transferred to a shaft that in turn is coupled to an electrical generator, such as in the Ri U.S. Pat. No. 3,942,025 or, in some instances, is directly coupled to a work producing element, such as in the Wiggin U.S. Pat. No. 3,212,470. These impellers provide various degrees of energy conversion efficiency that typically is substantially less than an optimum conversion efficiency. One reason for reduced energy conversion efficiency is that as the wind acts on the surface of the impeller, the impeller is rotated downstream by wind forces. As the impeller rotates upstream, however, the wind creates drag that tends to retard movement of the impeller and thereby reduces the energy conversion efficiency of the apparatus. Techniques have been developed to reduce upstream drag on the impeller by continuously changing the orientation of the impeller as a function of wind direction relative to the impeller surface, such as in Wurtz U.S. Pat. No. 4,186,313 or by providing air holes or flaps, as in Kephart, Jr. U.S. Pat. No. 4,177,014. These techniques have had a tendency to be inefficient because impeller orientation or wind spillthrough is not accurately controlled as a function of relative wind direction. Further, apparatus using these techniques are typically complex.
As another deficiency, such apparatus, although responsive to and effective with normal wind currents, are prone to damage in storm conditions or during turbulent or excessive wind conditions. There is therefore presently a need for wind powered energy conversion apparatus of the type described above that is relatively impervious to excessive wind currents, turbulence or the like. There further exists need to provide energy output modulation in such apparatus, i.e., to provide some means for controlling energy conversion efficiency whereby conversion efficiency may be manually or automatically reduced in response to excessive wind conditions to protect the conversion apparatus or driven load, or, to control the amount of energy to be supplied to a load as a function of load requirements.
In mobile installations, such as on the hull of a sea vessel to supply energy to operate the vessel or to operate accessories or on a land vessel to enable wind responsive energy to be supplied at remote locations, the impeller must, in practice, be relatively large to enable an adequate amount of energy to be generated. There is a potential problem, however, that occurs in such portable apparatus, wherein, in the case of a sea vessel, the impeller array is too large to pass between narrow straits or interferes in critical docking maneuvers. In the case of a land vehicle, the impellers are frequently too large to enable the vehicle to pass through a tunnel or other obstacle without first disassembling the impellers. There therefore exists a need to enable large impeller arrays to be folded or otherwise adjusted, without disassembly, to enable the impellers to occupy as little space as possible.
Accordingly, one object of the present invention is to provide a new and improved wind responsive power generating apparatus that lacks the various deficiencies of corresponding prior art apparatus of the type noted above.
Another object is to provide a new and improved wind responsive power generating apparatus that has improved energy conversion efficiency and durability.
Another object is to provide a wind responsive power generating apparatus that adapts to wind direction to reduce drag by controlling impeller spillthrough.
Still another object is to provide a wind responsive power generating apparatus wherein output power is modulated in response to wind conditions or in response to load requirements.
Another object is to provide a wind responsive power generating apparatus having impellers that fold and extend and retract to minimize occupation of space for improved transport ability.
In marine vessel applications of the type shown in the Wiggin U.S. Pat. No. 3,212,470, wherein rotating impellers are directly coupled to a submerged propeller to propel the vessel in water, there is a tendency for the craft to drift port or starboard because the rotating impellers tend to induce a clockwise or counterclockwise torque against the vessel. There exists the need, therefore, to compensate such an undesirable torque so that the vessel will maintain course. Alternatively, it is desirable to control such a torque to enable the vessel to be maneuvered or steered as an augment to or in lieu of, the standard rudder.
Another object of the present invention therefore is to provide a wind responsive power generating apparatus in a sea vessel, wherein clockwise or counterclockwise torques tending to undesirably steer the vessel port or starboard are eliminated.
Another object is to provide independent or augmented steering of the sea vessel using wind responsive impellers.
In high winds, great wave heights and listing of the sea vessel, it is desirable to manually or by electric or hydraulic action, have the capability to retract and promote stability by decreasing the length of the impeller; otherwise a listing vessel might cause an impeller to strike a high wave. The decreased length allows power collection in otherwise unmanageable wind or wave conditions.
Thus, another object of the invention is to take advantage of increased torque applied on an impeller shaft by wind by controlling the length of impeller cross arms.